The invention hereof relates to a dual purpose roller assembly that includes a spring biased axial caster member, where a prime use of such assembly lies in its incorporation into the sliding shelf disclosed in co-pending application, Ser. No. (Docket No. 255RJD), the contents of which are incorporated in its entirety in this invention. However, because of the unique design of the roller assembly hereof, there are other and diverse applications where the omni directional roller assembly of this invention may be used. For example, it may be incorporated into mobile furniture or equipment where protection against a vertical object or wall may be required. The best that the prior art seems to offer is a rotary caster, with or without a static bumper guard.
Exemplary prior art may be found in the following U.S. Patents:
a.) U.S. Pat. No. 5,899,517, to Murawa et al., discloses a stress-homogenized track wheel with a wheel disk which connects the wheel hub and wheel rim and decreases in thickness from the hub towards the rim. The disk's outer surfaces merges via three-center curves as radial generatrices targentially with the adjacent outer surfaces of the hub and rim. In order to suppress stress peaks and reduce the stress across the radial width of the wheel disk, the two outer surfaces of the wheel disk are defined in the radial central area geometrically by radial straight generatricies which intersect in the area between the three center curves on the wheel.
b.) U.S. Pat. No. 5,594,974, to Wattron et al., relates to a releasable caster for use with a movable structure having a bottom wall wherein the caster has a swivel connected yoke and stem with the yoke supporting a plastic wheel. The stem includes a manually operable spring biased rod that has an indentation between its ends and co-acts with a ball detent. A shell with a flange at its outer end is adapted to be received in an opening in the wall. The shell has an abutment, preferably in the form of a groove with the upper edge forming an abutment which cooperatively locks the ball detent or releases the ball when the rod is moved longitudinally or rotationally.
c.) U.S. Pat. No. 5,518,322, to Hickes, teaches a shopping cart wheel bearing which has a smooth inner race and an outer bearing holding with many semi-cylindrical openings. Each of these openings support a roller bearing or a pair of ball bearings which extend inwardly from the outer bearing to contact the inner race. As the wheel turns, each roller or ball bearing turns in the semi-cylindrical opening.
d.) U.S. Pat. No. 5,501,530, to Nagai et al., discloses a double-row, angular-type ball bearing for a wheel having a groove radius relationship such that the groove radius of the outer-ring raceway on the widthwise outer side with reference to the vehicle is larger than the groove radius of the outer-ring raceway on the width-wise inner side with reference to the vehicle. Included is a shoulder section formed in the first outer-ring raceway on the outer side and the second outer-ring raceway on the inner side to have a sub-section that curves in the opposite direction with reference to the main section of the outer-ring raceway.
While the prior art present different types of caster or roller members, none offer the unique feature of an omni directional roller assembly, where the axially mounted roller member is spring biased to provide a shock absorbing quality to the assembly. The manner by which the present invention defines this unique assembly will become apparent to those skilled in the art from the following description, particularly when read in conjunction with the accompanying drawings.